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Thinkjet repair

PostPosted: Fri Jan 23, 2009 8:45 pm
by Garth
I have an HPIL Thinkjet printer that hasn't worked the last couple of times I tried it. It goes through all the motions, but does not put any marks on the paper at all. I don't think it's the ink cartridges I tried, since they would put out fresh ink on the print head when poked gently with a big paper clip in the hole in the back. Is there something that commonly goes wrong with these printers? For the last several years, I've just been using my Epson printer with my HP-41 and 71, but it would be nice to be able to use old programs that print hi-res graphs, without re-writing them for the different Epson graphics commands and data format.

BTW, the original battery pack went out soon after I got the printer. When I found out how much they wanted for a new battery pack, I made myself a 7.8V power supply instead, which cost me fifty cents. I had everything I needed except one diode, and that diode was fifty cents. Before completing the power supply, I even tried the printer on a 9V alkaline battery. That worked fine, but the battery only lasted about six pages before becoming unable to deliver the current peaks. The battery was still almost new to other pieces of equipment that had low current demand.

Re: Thinkjet repair

PostPosted: Thu Mar 05, 2009 2:48 am
by Joe Horn
Garth --

My ThinkJet (before I traded it away :cry: ) often had intermittent contact with the pads on the ink cartridge. I don't know whether it was corrosion or dust or smog or what, but buffing the contacts with a Q-Tip moistened with isopropanol did the trick. It's worth a try.

Re: Thinkjet repair

PostPosted: Thu Mar 05, 2009 6:26 am
by Garth
I did try that, but have not dug into anything. I like making things, but not fixing things.

But! It's great to hear from Joe Horn, one of the giants in this field in the late 1980's as I remember. I seem to remember reading in maybe the CHHU Chronicle that someone even named an HP-71 string function after you as a humorous honor, which you said was "naughty" or something like that. I think it was JOEHORN$, which doesn't say much about what it does. I certainly look forward to the value you will add to this new forum.

Re: Thinkjet repair

PostPosted: Thu Mar 05, 2009 7:39 pm
by Joe Horn
Garth wrote:I seem to remember reading in maybe the CHHU Chronicle that someone even named an HP-71 string function after you as a humorous honor, which you said was "naughty" or something like that. I think it was JOEHORN$, which doesn't say much about what it does. I certainly look forward to the value you will add to this new forum.

Thanks, Garth! Yes, that was Professor Fred Lipschultz (sp?), who you can see standing next to me in this photograph. I was honored that Fred named his function after me; what was "naughty" was that he said he did so with my permission, which I would have never given for the reason you mention. What it did was take any graphic image destined for printing, and multiplied its size by any specified factor. Very handy for banner-type software!

Looking forward to HP-41 related chatter!